Atlas Copco introducing Tier 4i engines on mining loaders and trucks

Atlas Copco is introducing Cummins Tier 4i (interim) engines as an option on five of its underground loaders and one underground truck. The engines provide lower emissions and higher fuel efficiency.

The Cummins Tier 4i engines will be available as an option on the underground loaders Scooptram ST7, ST7LP, ST1030, ST1030LP and ST14, as well as on the underground truck Minetruck MT2010. In the standard offering, the equipment is powered by Cummins QSB6.7, QSL9, and QSM11 EPA Tier 3 / EU Stage IIIA diesel engines.

The Tier 4i engines feature improved performance and torque response via variable geometry turbocharging and an enhanced fuel system. This can provide up to 5% greater efficiency than the equivalent Tier 3 engine, said Atlas Copco.

The emission system includes a diesel particulate filter (DPF). Under the high load duty cycles typically experienced by mining loaders and trucks, the DPF can be expected to regenerate passively. The Tier 4i engines do not use urea-SCR.

In the United States, underground mining engines are exempted from EPA emission requirements. Instead, engines must be approved by MSHA (Mine Safety and Health Administration) and mine operators must meet ambient air quality standards, including MSHA ambient exposure limits for diesel particulate matter (DPM). MSHA approvals also assign additional mine ventilation rates based on the engine emission levels, typically either CO or NO emissions.

Tier 4i engines with DPFs can be a welcome solution for mines that retrofit their Tier 3 engines with particulate filters to meet MSHA DPM exposure limits. The adoption of Tier 4 engines in mines that have no DPM exposure problems is expected to be limited. Tier 4i engines—which utilize active, precious metal oxidation catalysts but no SCR systems for NOx control—can also produce increased NO2 emissions, potentially causing air quality problems in mines that experience elevated NO2 exposures.